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fix(llm-security): post-mcp-verify reads live PostToolUse tool_response field

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The PostToolUse hook read input.tool_output, but live Claude Code delivers the tool result as tool_response — so the indirect-injection scan on MCP tool output silently never fired outside the test harness (which sent tool_output). The hook now reads tool_response with a tool_output fallback for older harnesses/fixtures. +3 tests covering string and object tool_response and the precedence. Found via a live-session check during the v7.8.3 sweep; not one of the 52 MEDIUM-tier findings. Suite 2016/0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Claude-Session: https://claude.ai/code/session_01TcQyMTQfyrsAapaCMPxTtQ
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Kjell Tore Guttormsen 2026-07-18 11:00:34 +02:00
commit 32199965f2
4 changed files with 54 additions and 2 deletions
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@ -628,7 +628,7 @@ demonstrations — each with `README.md`, fixture, run script, and
| Version | Date | Highlights |
|---------|------|------------|
| **7.8.3** | 2026-07-18 | **Completion-review MEDIUM sweep — 47 verified fixes, no CRITICAL/HIGH.** 52 findings triaged (48 confirmed; 3 feature-requests + 1 non-defect scoped out; the #11 persistence detector and #27 AST-taint f-string recall deferred to v8). Supply-chain gate bypasses (npm bare-install blocklist skip, nested-key name derivation, yarn.lock false-BLOCK + Yarn Berry miss, `pip audit` no-op). Hook coverage (pathguard now `Edit|Write`; trifecta window no longer diluted by markers; pipe-to-shell interposition; bare provider-key patterns). Scanner robustness (HTML-pattern ReDoS 28s to 4ms; MCP-stdout memory exhaustion; VSIX redirect loop; scalar-policy TypeError; atomic cache writes). False positives/negatives (toxic-flow substring trifectas, TRG scoped-phrase FPs, leading-BOM HIGH, bare-`if:` Dependabot-spoof FN, reflog `reset` FP, diff duplicate-fingerprint mislabel, hex double-report). Parser divergence (YAML block-scalar key leak + indicators, ANSI-C octal/unicode, embedded-base64 to SIG, `.env.local` discovery). Docs consistency (scanner count 14, posture 16, red-team 72, SARIF version, dangling `ROADMAP.md`). 2013 tests, 0 fail. |
| **7.8.3** | 2026-07-18 | **Completion-review MEDIUM sweep — 47 verified fixes, no CRITICAL/HIGH.** 52 findings triaged (48 confirmed; 3 feature-requests + 1 non-defect scoped out; the #11 persistence detector and #27 AST-taint f-string recall deferred to v8). Supply-chain gate bypasses (npm bare-install blocklist skip, nested-key name derivation, yarn.lock false-BLOCK + Yarn Berry miss, `pip audit` no-op). Hook coverage (pathguard now `Edit|Write`; trifecta window no longer diluted by markers; pipe-to-shell interposition; bare provider-key patterns). Scanner robustness (HTML-pattern ReDoS 28s to 4ms; MCP-stdout memory exhaustion; VSIX redirect loop; scalar-policy TypeError; atomic cache writes). False positives/negatives (toxic-flow substring trifectas, TRG scoped-phrase FPs, leading-BOM HIGH, bare-`if:` Dependabot-spoof FN, reflog `reset` FP, diff duplicate-fingerprint mislabel, hex double-report). Parser divergence (YAML block-scalar key leak + indicators, ANSI-C octal/unicode, embedded-base64 to SIG, `.env.local` discovery). Docs consistency (scanner count 14, posture 16, red-team 72, SARIF version, dangling `ROADMAP.md`). Plus a live-protocol fix: `post-mcp-verify` now reads the PostToolUse `tool_response` field, so MCP-output injection scanning fires in live sessions. 2013 tests, 0 fail. |
| **7.8.2** | 2026-07-18 | **Silent-failure fixes from the completion review (HIGH).** Five defects, four sharing one failure mode: the check reported success without running. `hooks/scripts/pre-bash-destructive.mjs` did not block `rm -rf /` or `rm -rf ~` — the target alternation ended in a `\b` that cannot hold after a non-word character, so the bare forms the rule is named for fell through to WARN (exit 0, command executed) while `/etc` and `$HOME` blocked normally. `scanners/entropy-scanner.mjs` matched its test/fixture suppression against the **absolute** path, so any ancestor directory named `test`/`spec`/`fixture`/`mock` silenced every finding in the target and still returned status `ok`. `scanners/ide-extension-scanner.mjs` guarded only `parseVSCodeExtension`'s bare-`null` failure signal, not `parseIntelliJPlugin`'s truthy `{ manifest: null }`, so any malformed JetBrains plugin threw a TypeError that escaped `mapConcurrent`'s unguarded `Promise.all` and aborted the scan of every other extension. `scanners/content-extractor.mjs` detected obfuscated injections but did not remove them: a decoded-only `match[0]` never occurs in the raw text, so the literal replace was a no-op and the payload reached the LLM agent verbatim through `sanitized_content` — removal is now line-level, with unattributable multi-line payloads flagged `unstripped`. `scanners/lib/ide-extension-parser.mjs` emptied any plugin.xml field containing a character reference above `0x10FFFF`. No feature changes. 1901 tests, 0 fail. |
| **7.8.1** | 2026-07-18 | **Auto-cleaner command-injection fix (CRITICAL).** `scanners/auto-cleaner.mjs` syntax-checked candidate `.mjs`/`.js`/`.cjs` content via ``execSync(`node --check "${tmpPath}"`)``, where `tmpPath` derives from the untrusted scanned-repo **filename**. The v7.8.0 F-2 guard checks path containment but does not strip or quote shell metacharacters, so a file named ``x";<command>;".mjs`` closes the interpolated quote and injects a command — and `/security clean` runs live by default, making a hostile repository sufficient for arbitrary local command execution. Reproduced with a live PoC before the fix. Both subprocess sites (syntax check + the CLI scan-orchestrator fallback) now use `spawnSync` with an argv array, so no shell parses a path. Defense-in-depth: `applyFixes()` refuses findings whose `file` carries shell/control metacharacters, reported as `skipped`. Regression coverage is split across both layers so the guard cannot mask a re-introduced shell in the sink. No feature changes. 1865 tests, 0 fail. |
| **7.8.0** | 2026-06-20 | **TRG/SIG/AST deep-scan scanners.** Three new deterministic deep-scan scanners targeting the skills/agents attack surface, each with its own finding prefix, OWASP/AST mapping, policy block, and graceful-skip behaviour. **TRG** (`scanners/trigger-scanner.mjs`) inspects command/agent/skill `name` + `description` frontmatter for activation-surface abuse: `TRG-shadow` (name collides with a built-in and intercepts it), `TRG-baiting` (maximally-activating phrases that bait indiscriminate invocation), `TRG-broad` (generic name + universal-applicability claim); descriptions pass the decode pipeline first so obfuscated baiting still trips (LLM06/AST04). **SIG** (`scanners/signature-scanner.mjs`) is a pure-Node known-malware *identity* engine (webshells, reverse shells, cryptominers, hacktools) that tests each signature against both raw bytes and the decode pipeline (base64/hex/url/entity/unicode, homoglyph fold, rot13), so obfuscated known-malware a byte-matcher misses is still caught; rules ship in `knowledge/signatures.json` (LLM03/LLM02). **AST** (`scanners/ast-taint-scanner.mjs`) shells out to a PARSE-ONLY `python3` helper (`scanners/lib/py-ast-taint.py`) for variable-level, scope-aware Python taint analysis — higher recall than the ~70% regex `taint-tracer.mjs` — and falls back to the regex tracer when `python3` is unavailable, so the scan never hard-fails; the helper only `ast.parse`s the target and never executes it (LLM01/LLM02/AST02). Built behind a security-fix gate (F-1/F-2/F-3 shell-injection + path-traversal fixes landed first). 1863 tests, 0 fail. |